Process for discharging solid ores in cars or containers



Sept. 15, 1964 'r. J. DOOLIN 3,148,837 PROCESS FOR DISCHARGING SOLID ORES IN CARS OR CONTAINERS Filed Dec. 29, 1960 INVENTOR mamas J. 0004/,

ATTORNEKS United States Patent 3,148,837 PROCESS FOR DISCHARGING SOLID ORES IN CARS R CONTAINERS Thomas J. Doolin, 539 Center St., Ashland, Pa. Filed Dec. 29, 1969, Ser. No. 92,431 1 Claim. (Cl. 241-1) This invention relates to the removal of various materials which have been frozen in railroad cars or other containers, and more particularly relates to breaking loose such minerals as coal, ores, limestone and other materials in lump or particle form which have become frozen in railroad cars and in other transport means by a novel and economic process.

Many attempts have been made in the past to solve this problem which is not only very costly but very annoying; normally throughout the months of December through March, but in many northern latitudes from early fall to late spring this problem exists.

In the early practice or prior art the usual method of attempting to thaw out coal and other minerals which have become frozen in freight cars has been the use of pointed tools in the form of a pipe having apertures in its side and connected to a steam line. This type of process is haphazard, slow, wasteful of steam and completely ineffective. Attempts to improve this method by distribution of perforated pipes in the gondola or car is costly not only in capital equipment but also ineifective. It has also been proposed to run the car into heating chambers or sheds and let them remain there until the material has been thawed out. This method not only involves the construction of special and costly buildings but the operating costs are extremely high because of poor heat transfer and waste of steam as well as the long time required to produce any results whatsoever because of the inefficiency of the method. The system is also inefficient because of the lack of flexibility and difficulty in locating the buildings properly.

' Some proposals have been made recently for the installation of special sheds wherein the frozen cars are subjected to treatment with infra-red ray equipment re quires special installation and since it depends primarily on heat transfer as in the case of the use of steam it is subject to the same difliculties which makes the process very expensive and long drawn out, with high capital cost.

It is obvious from the above discussion that all the proposals heretofore made are either too costly in operating expenses and costs or in capital investment or in both and, moreover, they are inefficient and impractical. Other devices proposed such as mechanical shakers while perhaps suitable for ordinary uses to assist in unloading cars of minerals are highly questionable from the viewpoint of loosening and shaking free frozen cars. Also since the energy impacts upon which the process depends are transmitted through the sides of the car itself in hammer-like blows, the wear and tear on the car and consequent cost would be substantial. Other methods such as the use of ordinary salt, that is, sodium chloride, to thaw the frozen car is not only inefiective because of distribution difficulties but is costly since it requires from about 500 to 1000 lbs. of salt per carload and even so is ineflicient. The same objection would apply to the use of calcium chloride and, in addition, this material tends to hydrolyze in water and produce an acid which corrodes the car and shortens the life thereby.

It is obvious from the above discussion that none of the methods heretofore proposed to thaw out frozen cars Patented Sept. 15., 1964 The present invention relates, in general, to the use of combustible fluids, that is, gases or liquids mixed with sufiicient air to form an explosive mixture so that when ignited the said container will create a series of explosions of suflicient force to blast loose and shake out said minerals from the said container. The combustible liquids may comprise petroleum or hydrocarbon fractions or combustible derivatives thereof particularly the lighter commercial products such as gasoline, casing head gasoline, cleaners naphtha and the like. Lighter coal tar derivatives such as benzene, toluene, and xylene, may likewise be employed, although the petroleum hydrocarbons are more desirable because they are less expensive and in general more suitable. Other combustible liquids may be used such as various alcohols, for example, grain alcohol, that is ethyl alcohol, methyl alcohol, propyl alcohol and the like as well as acetone. Wood tar distillates may also be employed, particularly the lighter fractions thereof. I may also employ the lightfractions resulting from the pyrolysis of oil shales, lignites, and the like which, in general, are hydrocarbon fractions.

In addition to the liquid hydrocarbons and other liquid combustibles mentioned above, I may employ gas, particularly the hydrocarbon gases such as natural gas (which consists mainly of methane), ethane, propane, butanes and the like. The combustible gases (which may also include in some unusual situations such combustible in, said gasoline being introduced in sufficient amounts to form an explosive mixture with the air contained in the interstitial spaces between the lumps and particles of the frozen minerals, that is, the coal and the ores and thereafter igniting the explosive mixture to create a series of small explosions (e.g. in each pocket of the said explosive mixture), having suflicient explosive force to blast loose and shake out the said frozen minerals, that is, the coal and ores to permit their ready removal at minimum expense and capital investment.

In accordance with my present invention a liquid or gaseous combustible of the type mentioned above and, more particularly, a petroleum derivative such as gasoline or a liquid containing similar hydrocarbons may be poured, sprayed, pumped or otherwise injected or introduced into the car, preferably along the top and ends of the same to permit distribution of combustible hydrocarbons or other combustible throughout the interstices or pockets between the lumps or particles of the mineral comprising coal, ores, and the like to form an explosive mixture, therein. The combustible, for example, the gasoline is allowed to permeate throughout the mineral lumps and particles and to vaporize and mix with the air.

in thespaces between the same, thereby to form an explosive mixture which when ignited by an open flame, electric spark, or any detonating device will cause a series of explosions-that will blast loose and will break up the frozen ores or minerals including coal and will set up a force in the railroad car or other container that will cause vibration and shakeout or release of the pieces of frozen minerals or other materials contained in said car.

When the combustible gases are used they are preferably introduced at the bottom of the car, if they are lighter than air, or otherwise at a point so that they will disseminate throughout the car with minimum loss.

While I do not intend to be bound by an explanation of the mechanism of the principles upon which my invention is based, the following appears to be a reasonable explanation in view of the results which I have obtained. In the normal mining and processing of coal it would contain about 2 to 4% of moisture when loaded for transportation. Iron ores would contain from about 5% to about under the same conditions. With a great deal of rain or snow prior to or after loading the coal or other minerals in the car these figures would be increased somewhat. In any event, when the cars are subjected to freezing conditions a film or coating of ice forms around each lump or particle of the mineral and causes it to adhere to the neighboring lumps or particles resulting in a solid mass widiin the car which cannot be removed without loosening the ice. My invention is thus addressed to the latter problem. The best work done to date which also conforms to my own observations on the question of the range of concentrationsby volume of hydrocarbon vapor, for example, vaporized gasoline in air which will form explosive mixtures shows that a minimum concentration of gasoline and air to form an explosive vapor or mixture is about 1 /2% and the maximum concentration is about 6%. It has also been shown, which conforms to my own observations and tests that the voids in granular materials or lumps such as minerals enerally including coal, ores and the like varies from about 35% to about 50% more or less depending upon actual sizes but more particularly upon size distribution. In the case of very large lumps, of course, but of more or less uniform size the air space may even be greater and the same holds at the lower range where the sizes are uniform and very fine. On the basis of 50% voids or interstices a 50 ton car or gondola containing 1800 cubic feet would have about 900 cubic feet of voids or air spaces, and on the same basis, a car of 75 tons capacity would contain 25 ()9 cubic feet or 1250 cubic feet of air space. One gallon of gasoline when completely vaporized produces about 32 cubic feet of vapor (with some variations depending on the boiling range, vapor pressure, etc.) and simple calculation will show when the percentage of gasoline vapor in the air.

voids or spaces in the car are within the explosive range making some allowance for distribution. I have carried out a series of tests in connection with the above and in all cases my observations coincide with my calcula tions and vice versa. 1 have also observed that the gasoline when introduced into the car in the proper proportions to form an explosive mixture is'disseminated within a matter of several minutes and that when the explosive mixture is ignited, for example, at the bottom of the car where the discharge takes place (or in an aperture designed for that purpose) that the series of explosions are complete within approximately 30 seconds to one minute: and that judging by the nature of the explosions they take place at sequence, that is, in a chain-like series of reactions resulting in hundreds of explosions. It would appear also since the explosions originate at the point of ignition and travel in all directions that they do not consist of a single series, but a group of such series of explosions, each one being triggered by its neighboring pocket and each explosion being of sulficient force to break and fracture the coating or film of ice and releasing the individual lumps and particles to permit their ready removal from the car. The nature of the explosions are thus totally unlike the use of high explosives such as nitroglycerine, dynamite, amatol, picric acid, trinitrotoluene and the like. The latter are of an instantaneous shock type which may take place a thousand times or more faster than the explosions of my invention.

Although the effect of an explosion of a mixture of approximately 1000 cubic feet of air, containing complete- 1y vaporized therein, about two gallons of gasoline, could be very dangerous if it were carried out in a room, for example, 10 x 10 x 10 and would without question destroy the building: However, as described above in connection with my invention the same quantity of explosive mixture in the voids or pockets, or explosive mixture be tween the lumps and particles of coal or ore cause an extremely large number of relatively small explosions which are completely safe and harmless so far as any personal injury or damage to the car is concerned, but which are exceedingly effective in loosening the contents f the frozen car for removal. It will thus be seen that the results of my invention are highly unexpected as well as eliicient and very economical with low operating costs and only minor capital investment and that my invention depends primarly upon breaking loose of the materials by explosive vibrations rather than by thawing of the ice which is the case with the prior art.

Having described the principles underlying my invention I shall proceed to give a detailed description of the manner in which it is carried out in connection with the equipment used therewith.

The accompanying drawing shows the arrangement of a freight car, of an ordinary steel gondola type, used for carrying coal, ore, limestone or other material of the type referred to above and which may be employed to illustrate the process of my invention and the equipment used in connection therewith. Since the invention is not concerned with all the details of the car or gondola the description of the latter will be limited to elements which have a direct bearing on my invention. The car or gondola 1, is supported by center sill or structural member 2 and by the usual bolsters 3 and 3' for supporting the body of the car. The bottom of the car 4 and 4 slopes towards the middle or center of the car and a central sloping portion 5 and 5' serves to deflect the contents of the car to, coal, etc. in either direction towards the doors 6 and 6' which are hinged at '7 and 7 to allow discharge of contents of the car. -When the doors are opened the iced contents e.g. the coal, of the car fail to discharge as they would normally do because the lumps and particles of the coal are frozen and are held inplace by the ice practically as a solid mass. The gasoline (or other combustible liquid) is introduced at either end, and generally and preferably at both ends lit and It? of the car and at the top thereof and flows through the interstices which comprise poclrets of air or air spaces generally between the lumps and particles or" the coal at the same time vaporizing and mixing with the air in the interstices to form an explosive mixture as already described.

After allowing several minutes (about 1 to 5) for the gasoline to percolate through the coal and to vaporize in the air spaces the mixture may be ignited at the open doors or through apertures in the doors or the bottom of the gondola i.e. the open hopper or adjacent thereto. Ignition of the air-gasoline mixture when the content of gasoline is adjusted i.e. the amount of gasoline introduced, in relation to the interstitial air to form an explosive mixture preferably in the range of about 1.5% to 6% of gasoline (about 1 to 4 gallons of gasoline for each car of 50 to tons capacity, averaging about 2 gallons) vapor by volume in the mixture causes an explosion of a vibratory character wherein the explosions in each pocket of air-gasoline explosive mixture travels rapidly from one pocket to another causing numerous explosions of a vibratory character which break the ice films or bridges connecting the lumps of coal and permit their removal in the normal manner. The time necessary for the explosions to travel throughout the car is very small generally of the order of thirty seconds to injury or damage occurs (either to the car or the operator).

The gasoline or other combustible fluid may be introduced manually by pouring the same from a container holding one to several gallons or it may be pumped in or introduced from a blow case from a bulk supply, or by other suitable methods and means.

Ignition of the explosive mixture may be done simply by an open flame (preferably with oil soaked cotton waste at the end of a rod, or by a suitable ignition device such as in the use of batteries and a spark or induction coil, or other electrical devices for remote control as desired. I may also employ other combustible liquids in addition to gasoline e.g. liquid hydrocarbons, generally adjusting the amounts of liquid added to obtain a mixture within the explosive range i.e. about 1.5 to 6% by volume of the hydrocarbon vapor in the air-hydrocarbon mixture. For example, the use of cleaners naptha (about 40 mm. Hg vapor pressure at 60 P.) which, because of.

its lower vapor pressure would be on the low side of the explosive range for the same volume added, i.e. the amount added must be increased somewhat because of the percentage of vapor produced may be about one fourth of that produced from very light gasoline under the existing'conditions. Kerosene which has a still lower vapor pressure would require still more liquid and also be more diificult to handle. On the other hand very volatile hydrocarbon products such as casing head gasoline would be more readily vaporized e.g. more than four times the vapor as from cleaners naphtha under the existing conditions. In all cases the amount required should be estimated so as to be in the explosive range; and light hydrocarbon products generally may be used and the amounts used may be varied somewhat depending on vapor pressure, for example, the more volatile hydrocarbon products will vaporize readily and completely and therefore will require only the normal amount of 1 to v4 gallons (average 2 gallons) of gasoline per car of 50 to 75 tons of coal. One gallon of average motor gasoline when completely vaporized produces about 30 to 32 cubic feet of vapor and the average two hopper car of (50 tons capacity) contains about 1800 cubic feet, and four hopper about 2500 cubic feet (75 ton capacity). On the basis of 50% air space (see following discussion) 1 gallon of gasoline will produce 3.6% vapor for the 50 ton car and 2 gallons will produce 5.2% vapor for the 75 ton car both of which are in the explosive range of 1.5 to 6% vapor in the explosive mixture.

For the above reasons ordinary motor gasoline is satisfactory in all respects since it has a sufiiciently high vapor pressure to vaporize satisfactorily and can be readily procured almost everywhere; and its use is confirmed in practice.

While theoretical calculations will show more or less exact amounts of gasoline to be added there is considerable flexibility in the explosive range of- 1.5 to 6% of gasoline vapor. On the other hand, gasoline itself and related hydrocarbon mixtures is a mixture of hydrocarbon compounds, as well as in different grades as pointed out above. Alsoas discussed below air space also varies somewhat. Moreover, the distribution of the gasoline is random to some extent so that a reasonable excess will give satisfactory results and in general the results are very satisfactory using the above general rule and keeping within the desired range of 1.5 to 6% vapor more or less. Some consideration is to be given also to the variation in sizes of material e.g. the coal, ores, and other minerals as this affects the interstitial air space and to some extent the amount of gasoline or other liquid combustible to be added especially where it is desirable to determine the vapor concentration and position within the explosive range more accurately. In most cases the following information will sufiice. The range of air space is from about 35% to about 52%. The latter figure is for perfect spheres of uniform sizes. The first figure is for a distribution of sizes. As examples sizes varying from /3 to /2 inch showed 37%; from /2 to 1 inch 42%; from 1 to /2" 47.5%. Thus when the material is coarse the gasoline added is inthe higher range, and when fine and in addition not uniform the lower range is indicated.

Some knowledge of the size is desirable but in any event as pointed out the relatively wide range of explosive limit and the use of a small excess assures satisfactory results in the range of 1 to 4 gallons of gasoline. Moreover, the total air space (and hence the average) may be readily determined by a simple test. The latter consists in filling a vessel of known volume to the mark with the coal, ore or other mineral and then measuring the volume of water (or other liquid) which may be added to the mark. The latter gives directly (by simple calculation) the percentage of interstitial or air space. (For very porous substances a correction may be made for apparent density, but for coal and most materials the direct determination is sufliciently accurate for operating purposes.)

The following specific examples will further serve to illustrate my invention.

Specific Examples (1) To a frozen carload of coal of the steel gondola type with a 75 ton capacity was added 2 /2 gallons of ordinary motor gasoline, introducing 1% gallons manually at the top of each end of the car. The gasoline was allowed to permeate throughout the voids and air spaces between the lumps of coal for approximately 35 minutes. The doors of the discharge hopper in the middle and bottom of the car were open during the introduction of the gasoline. With all personnel clear of the car the explosive mixture was ignited at the discharge doors of the hopper by means of a torch consisting of cotten waste attached to the end of a six foot steel rod saturated with gasoline and ignited before approaching the car. The operator is thus approximately six foot away from the car. From the moment of. ignition until about thirty seconds later a muffled series of explosions not loud but audible could be heard accompanied by vibrations throughout the car and low cracking sounds. Within less than a minute from the time of ignition the car is ready for discharge, i.e. the contents of the car are moving and in fact this discharge had begun in a normal manner, that is, from the hopper doors. In this example the size of the coal was essentially from one inch to two and one half inch mesh or diameter which is essentially from the viewpoint of size a mixture of egg and stove coal. The estimated void or air space was approximately 50% and the volume of the car being approximately 2500 cubic feet the voids or air space would be about 1250 cubic feet. Vaporized gasoline occupied about 77 cubic feet on the basis of 31 cubic feet of vapors per gallon.

On this basis the concentration of gasoline vapor in the air or void space is 6.15% which is at the top limit of the explosive range but in practice was found to Work satisfactorily.

Example 2 In the second example the car was a steel gondola filled of the car at thetop, one gallon was introduced at each end. About 3-5 minutes was allowed-for complete dissemination of the gasoline throughout the air space or void. The mixture was ignited in the same manner as was described in Example 1- and within thirty seconds to one minute the formerly frozen contents of the car was readily discharged. Calculation of the gasoline vapor content of the air in the voids or air spaces on the above basis showed it to be 6.2%, the top of the explosive range on a theoretical basis but nevertheless satisfactory, thus showing some leeway for practical operation;v

responding to stove and chestnut coal to 2" diameter 7 in size distribution with void or air space of approximately 48% had introduced therein at each end and at the top of the car a total of two gallons of gasoline; that is, one gallon at each end of the car. About four minutes was allowed for dissemination of the gasoline and vaporization thereof throughout the voids and air spaces within the car. An electrical sparking device making use of an induction coil and dry batteries in a single unit so arranged that the sparking device in the opening at the bottom of the hoppercould be connected by appropriate wires for any convenient distance to the appropriate terminals on the induction coil. The circuit was completed for ignition by merely pushing the button to close the switch. Within thirty seconds to one minute an ensuing cries of explosions within the car loosened the entire contents and permitted discharge thereof. The total content of air or void space was 1200 cubic feet approximately. On the basis of 32 cubic feet'of vapor per gallon of gasoline the concentration of gasoline vapor in the airvapor mixture was 5.35% well within the explosive limits and the results were satisfactory.

Example 4 A frozen carload of coal of the gondola type consisting of large lumps from 4 inches to 6 inches in diameter for industrial use was treated to thaw out the same. The estimated void space or air space was approximately 52%. The car was normally a 75 ton gondola type. A total of two gallons of gasoline, one gallon at each end of the car and at the top was introduced into the car and after three to four minutes was ignited with the sparking Example A frozen carload of coal of the gondola type; the coal being in very large lumps of the order of that used in Example 4 for industrial use and having an air space of approximately 52% had introduced therein at the bottom of the gondola a compressed gas corresponding to natural gas (and consisting primarily of methane containing about 95% of this hydrocarbon gas). The gas weighing not much more than one half that of an equal volume of air tended to rise throughout the void space between the lumps of coal in the car and metering was accomplished as quickly as possible. The total air volume being about 1300 cubic feet, approximately 10% of this volume, namely 130 cubic feet of methane was introduced in the manner described. The explosive limits of methane is between 5 and 14% of the volume of the air so that the amount introduced was be tween the lower and upper limits. The tank of gas was at a remote distance with a line leading therefrom to the bottom of the hopper and extending well into the car. Ignition was accomplished by the sparking means already described and the results in discharging the car were satisfactory. (it may be remarked, however, that this procedure while satisfactory is somewhat more difficult to control than the use of gasoline.) In this connection also it may he mentioned that other gases such as ethane, propane and the like including gases from the cracking process may be employed; and, in general, when gases are used in connection with the type of operation described somewhat more elaborate equipment for control is required.

Example 6 A frozen car of limestone in sizes 1" to 2 /2" having an air or void space of approximately 50% had introduced therein at the top and the ends of the car a total of two amass? a gallons of gasoline, one at each end of the car; which vaporized in the air or void space in the frozen car of limestone of approximately Approximately four minutes after the introduction of the gasoline into the car, ignition was accomplished by means of an open flame type of igniter as described in Example 1 and within thirty seconds to one minute the car was being dis-- charged: All of the connecting surface ice having een ruptured and fractured and the carload of limestone being completely loosened. The total cubic contents of the car was 2500 cubic feet. The air or void space was 1250 cubic feet. The percentage of gasoline vapor in the explosive mixture was found to be 5.1%. Operation and discharge of the car was satisfactory.

Example 7 oline vapor was estimated at 56 cubic feet which brings the percentage of gasoline vapor in the explosive mixture to approximately 6%, that is, the upper limit. The operation was satisfactory.

Example 8 A frozen car of iron ore of the type and size described in Example 7 was treated to loosen the same but instead of introducing 3 10 of a gallon of gasoline at each end and at the top of the car the amounts of gasoline introduced at each end and at the top of the car was 9 of a gallon. Approximately 4 minutes was allowed for dissemination of the gasoline and the explosive mixture ignited in the usual manner. ore could be discharged satisfactorily out the bottom of the car, although the concentration in Example 7 is preferred.

Example 9 The conditions employed in Example 7 were applied to limonite, a somewhat lighter iron ore than the hematite weighing approximately 213 lbs. in place on a practical basis and about lbs. per cubic foot for the loose ore. Distribution of sizes for the limo-mite was somewhat greater so that the air space or void was approximately 46% making a total volume of air of 870 cubic feet. A total of 1.5 gallons of gasoline or approximately .75 gallon was introduced into the car at each end and at the top thereof. After approximately four minutes to permit dissemination of the gasoline and explosive vapors throughout the car the mission was accomplished as described before. Within one minute the car was being discharged. The total volume of gasoline vapor in the air was approximately 48 cubic feet making the percentage of gasoline 5.5%. Operation was satisfactory.

Example 10 car having a volume or capacity of about 1875 cubic feet.

was used and would thus contain about 940 cubic feet of air space. A total of 1.6 gallons of gasoline making of a gallon for each end of the car andat the top thereof was introducedinto the car. Within two to four minutes the explosive mixture was ignited at the bottom of the car and within one minute discharge began. Re-

After one minute it was found that the The magnetite was of medium 9 moval of the ore from the car was satisfactory. The percentage of gasoline vapor in the air space was calculated to be about 5.5%.

Example 11 A carload of sea gravel of Ms" to /2" diameter approximately with fairly uniform distribution of the sizes mentioned was treated to loosen the gravel. The car was of the gondola type of about 75 tons capacity containing a volume of 2500 cubic feet. The air space was estimated to be about 38%, making a total of 950 cubic feet of air. The amount of gasoline added was a total of 1.8 gallons, that is about 7 of a gallon was introduced at each end of the car and at the top thereof. After an interval of three to five minutes the explosive mixture was ignited at the hopper at the bottom of the car and discharge began in somewhat less than a minute. The unloading of the car was satisfactory. The percentage of gasoline vapor in the air space was calculated and found to be 6.1%.

Example 12 A frozen carload of coke weighing about 35 lbs. per cubic foot, that is, about 70% of the weight of bituminous coal and having an estimated (pore) content of about 20% in fairly large lump sizes from about four inches to six inches. The gondola car holding about 75 tons having a volume of about 2500 cubic feet. The normal air space was about 50% making a total air space of about 1250 cubic feet. About three gallons of gasoline total was introduced into the car, one and one half at each end of the car and in the top thereof. After an interval of about five minutes ignition was effected at the bottom of the car and discharge began in about one minute. The amount of gasoline vapor in the air space was calculated and found to be about 7.6%. This is somewhat excess over what would normally be used but allowance was made for the porosity of the coke and for some absorption in the coke itself. On the assumption of about 20% absorption (which is quite likely) vapors in the air space itself would be slightly in excess of 6% the upper limit of the explosive mixture. Since the result was satisfactory practice confirmed the calculation.

With reference to the above examples wherein gasoline is used I may employ other hydrocarbons such as the lighter products benzene, toluene and the like making the necessary adjustments for vapor volume and similarly I may employ the naphthene hydrocarbons such as cyclohexane, cycloheptane and the like. I may also employ other combustible liquids such as the alcohols and the ketones referred to above, but for economic and other reasons, gasoline and similar mixtures of petroleum hydrocarbons are preferred.

It is also obvious from the above discussions and examples that I may apply the principles of my invention to the discharging of frozen cars containing solid materials.

in a subdivided form consisting of lumps, granules, grains, and particles from a container, for example, a car and that such solid material may consist of minerals and ores,

10 generally, including both the metallic and non-metallic minerals.

While I have listed coals, which, of course, includes both anthracite-and bituminous coals as representative of solid fuels, I may also include in this class lignites, canal coal and the like as well as coke which is derived from the coals. Likewise I have mentioned by way of illustration and also because of their importance the ores of iron including hematite, magnetite, and limonite. I may also treat by my process a large number of ores, in fact, including all of those Which are transported in economic quantities. These ores and minerals generally would comprise the oxides, sulphides, carbonates and other compounds of copper, zinc, tin, lead, manganese, aluminum, magnesium, lithium, cobalt, nickel, chromium, tungsten, etc. Obviously, other ores of the metals may be recited which in effect Would exhaust the periodic system in respect of those metals, the ores of which are economically produced and transported. Among the nonmetallic materials, those which may be mentioned are limestone, which has already been cited, phosphate rock, sulphur, graphite, greensand, various earths and clays such as fullers earth and kaolin, crushed rock, gravel, and sand. This class also has many other materials which occur in a subdivided form, that is, in lumps, granules, grains and particles which may be cited but it is believed that sufficient examples have been named to fully show the application of the process with respect to the materials to be treated.

The data and examples referred to above are shown for illustrative purposes only and are not to be construed in a limiting sense as there are many variations of materials and conditions of treatment which may be included without departing from the broad scope and spirit of my invention.

I claim:

A process for freeing minerals such as ore and coal for discharge from a coal car, the mineral being in lumps and frozen in situ so that it cannot be discharged from said car in a normal manner, there being air pockets between adjacent mineral lumps comprising the steps of introducing gasoline to said car, permitting the gasoline to evaporate and be disseminated in vapor form throughout the air spaces between the lumps, there being an explosive mixture with the air in each of the air spaces comprising about 1.5 percent to about 6 percent of gasoline vapor, and thereafter igniting the explosive mixture to create a series of explosions in the air pockets and to loosen the frozen mineral so as to permit discharge of the same from the car.

References Cited in the file of this patent UNITED STATES PATENTS 1,631,290 Sheedy et a1 June 7, 1927 2,010,981 Dean et a1 Aug. 13, 1935 2,305,724 Leutzeschwab Dec. 22, 1942 2,494,695 Fisher Jan. 17, 1950 FOREIGN PATENTS 1,139,131 France Feb. 4, 1957 

